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Topband: FRONT END PROTECTION

To: <topband@contesting.com>
Subject: Topband: FRONT END PROTECTION
From: magoo@isp.on.ca (Mr. Magoo)
Date: Tue, 10 Sep 2002 19:37:10 -0400
After blowing up the antenna transfer board on my FT990 as a result of a
very close lightning strike, I built up a relay switcher which (a) grounds
the Beverage RX feed from the remote switch box when power is turned off
and likewise grounds the RX-only input jack on the radio  (b) grounds the
RX-only jack and the Beverage line feed during TX.  The contact spacing on
the radio's
RX-only changeover relay is very small...the relays I am using have 10A
contacts with wide spacing.  I use a "Y" jack to the amplifier's PTT line
for control.

Nothing difficult here...just a couple of relays and a selector switch.
Perhaps a couple of diodes would be a good idea to deal with any spikes
which jump the relay contacts (but then...if they can do that, diodes would
probably be ineffective and I would be buying a new radio!!)

Bill, VE3NH


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